import random
stu = []
for c in "ABCDEFGHIJ":
    yz = (c,random.randint(40,100))
    stu.append(yz)

print(stu)
score = sum( [ s[1] for s in stu ] )
print("平均分:", score / len(stu))
stu2 = [ s for s in stu if s[1]<60 ]
print(("不及格人数:", len(stu2)))